PHILADELPHIA (CBS) – Many roadways were merely wet on Tuesday morning around the Delaware Valley, but with temperatures hovering around the freezing mark, some surfaces were turning icy.

Pedestrians, especially, were finding that sidewalks were treacherous in the early morning hours of Tuesday as a light drizzle settled on cold surfaces and froze.

The Departments of Tranportation of Pennsylvania, New Jersey, and Delaware were all prepared for a long battle if necessary, laying a coating of salt brine on major highways in advance of the expected precipitation.

PennDOT alone has more than 400 plow and salt trucks plus private contractors at the ready, plus tons of extra salt and anti-skid material.

Salt crews were responding to icy spots when reported.

But it wasn’t always enough: on the Northeast Extension of the Pennsylvania Turnpike, a jackknifed tractor-trailer closed all northbound lanes between Mid-County and Lansdale for several hours this morning.

In the city of Philadelphia, crews from the Department of Streets spent some time clearing storm sewer inlets, pushing excess snow left behind by plows to the curbs. The city was also trying to catch up with plowing and salting on secondary roads.

On Monday, mayor Michael Nutter said he was “not satisfied” with the condition of small streets around the city and asked residents to be patient as streets department crews continued their work (see related story).

With the possibility of icing in the forecast, electric utility companies have brought in extra crews, anticipating possible power outages over the next 24 to 48 hours. Officials were urging residents to have fresh batteries in a portable radio to get information if the power goes out.

SEPTA’s web site was reporting one Regional Rail line — the West Trenton — with 18-minute delays. SEPTA says its crews have been treating parking lots and platforms but urge caution when walking on train platforms or at bus stops.

At Philadelphia International Airport, the FAA was reporting weather-related delays averaging nearly 50 minutes due to low cloud ceilings. Travelers are urged to contact their airline or the airport’s web site, PHL.org, for updated information.